LDEO Research Blogs

The rocks beneath the coastal plain of Georgia were at the center of the most fundamental tectonic events to shape eastern North America: continental collision around 290 million years ago to form the super continent of Pangea; continental breakup leading to the formation of the Atlantic Ocean beginning around 230 million years ago; and one of the biggest magmatic events in Earth’s history around 200 million years ago, the Central Atlantic Magmatic Province. A record of these events and possible relationships between them is preserved by structures in the crust of southern Georgia, including a suture between two different types of continent, the largest failed rift basin along the east coast of North America and igneous rocks from the Central Atlantic Magmatic Province. We will collect seismic refraction data, which can be used to image structures in the crust to understand these tectonic events. During March 2014, over 1000 geophones will be deployed along a ~300-km-long profile across the suture and the basin, which will record sound waves generated by a series of controlled blasts spaced ~20 km apart. The speed that sound waves travel through rocks varies with rock type. We will use these data to create velocity models that reveal the distribution of igneous rocks, variations in the thickness of the crust and variations in crustal composition. Besides a better understanding of fundamental tectonic processes, other benefits of this program include training and education of students, and characterization of basins and igneous rocks that might be good targets for carbon sequestration.

The South China Sea is one of the most geopolitically contested marine realms on earth. But it is also of keen interest to geologists who want to understand how this ocean basin, bordered by China, the Philippines, Malaysia and Vietnam, opened up. On an International Ocean Discovery Program cruise aboard the JOIDES Resolution, scientists will drill through seafloor sediments to understand how the basin reached its present form. Marine geologist Trevor Williams of Lamont-Doherty Earth Observatory is directing downhole logging operations. Follow his dispatches from the ship here.

Driven by processes in the deep earth over millions of years, the East African Rift is slowly tearing the continent apart, producing earthquakes and volcanoes along its 2,400-mile track. A scientific team including Donna Shillington, James Gaherty and Cornelia Class of Columbia University’s Lamont-Doherty Earth Observatory is working in Malawi and Tanzania to understand the causes, the long-term evolution, and the real-time hazards.

We are conducting a seismic program in the Deep Galicia Basin of the northeast Atlantic Ocean west of Spain. The goal of the proposed research is to collect data necessary to study the rifted continental to oceanic crust transition in the Deep Galicia Basin west of Spain.

Polar ice is home to large communities of algae that thrive in the frigid Arctic environment, including microscopic bacteria, unicellular algae, diatoms, worms and crustaceans. These tiny organisms have a big impact on the marine ecosystem and the entire planet -- including us. Andy Juhl and Craig Aumack, scientists from Lamont-Doherty Earth Observatory, are in Barrow, Alaska studying algae in and below sea ice, and how our warming climate may impact these important organisms.